A pressure washer may include a pump configured to receive a relatively low pressure fluid inlet and provide a relatively high pressure fluid outlet. The pressure washer may also include an engine coupled with the pump for driving the pump. An electric starter may be engageable with the engine for starting the engine. A flow sensor may be configured to provide a control signal in response to detecting fluid flow through the pump. The pressure washer may also include a controller configured to actuate the electric starter in response to the control signal when the engine is not operating.

The method according to the invention is implemented in an alternator-starter (1) comprising phase windings (u,v,w) connected to an inverter (3) linked to an onboard electrical network (2) powered by a battery for operation as a starter. The invention involves controlling the inverter in a chopped full-wave control mode when the rotational speed () of the alternator-starter is lower than at least a threshold speed and in a full-wave control mode when the rotational speed is higher than the threshold speed. According to a specific embodiment, the switching between the chopped full-wave control mode and the full-wave control mode takes place according to a hysteresis cycle using two predefined threshold speeds.

A desired effective voltage can be ensured with certainty in a preheating control. An operation control part 52 reads a correction value c with respect to a battery voltage Vb at the time of performing correction based on preliminarily stored correlation between a battery voltage Vb of a vehicle-use battery and a correction value c (S104, S106), and compensates for lowering of an effective value of a pulse voltage by adding a correction value c to a duty ratio calculated by a predetermined arithmetic expression thus ensuring a desired effective voltage with certainty in a preheating control.

A battery booster for jumpstarting a vehicle having an external battery. The battery booster may include a processor, a set of terminal connectors, a power supply, and a power-management circuit. The set of terminal connectors may be configured to couple with the external battery or an engine that is electrically coupled with the external battery. The power supply may include a lithium battery configured to supply a starting current to jump start an engine. The external battery may have a first nominal voltage, while the lithium battery may have a second nominal voltage that is greater than the first nominal voltage. The power-management circuit operatively coupled with the at least one processor, wherein the at least one processor is configured to transfer power selectively between the external battery and the power supply. The processor is configured to perform a pre-charge function and/or a back-feed function via the power-management circuit, which may employ a pulse width modulation (PWM) driver.